I just noticed a scratch on my screen a few days ago as well. I had the BodyGuardz then took it off because but it ruined the crisp display of the iPhone. I'd steer clear of it, only thing I have to show for it is a scratch...
Sorry to hear that. Not sure how to help with that except try the crystal film.
What's funny is the Apple Sales Associate tells me, "Not sure why you want to get the crystal film. Personally? It's a waste of money. My buddy who works here with me took his car keys and went at it on the screen and not one scratch showed up. He just attacked his screen with his car keys and nothing happened to it. The crystal film is a waste of money."
The iPhone screen is glass. Not sure how you can possibly "buff" out scratched glass without using some techniques that would do more damage. I bought an iPod screen care kit from DLO, before I found out the iPhone and Ipod touch had gone to glass, so it was worthless for my situation. I have no scratches, but the kit was on clearance at BestBuy for nearly 90% off (only $2.99). So I thought what the heck, it even comes with a nice polishing/cleaning cloth.
I did find a use for the kit though. It took the scratches out on my eyeglasses just great.
I too, use a case-mate crystal film. Not so much for the scratch resistance, but the additional strength an adhesive film adds to a glass surface that helps prevent cracking or shattering. Sorta like the use of masking tape when transporting a mirror.